Passive House / NZEB Open Day 13th-15th November

Once again many people around the country will be opening their doors to visitors to showcase their project.

Many low energy & Passive Houses will be on show. If you have not been to one, go! It is a great insight into why the Passive House concept is a no-brainer for all building projects.

see for details.

We opened our doors last year to over 30 people but sadly cannot do it this year.

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Self Build Magazine

Our building project has been featured in Self Build magazine, Winter issue.
Thanks to Astrid for the article and to Dermot Byrne for taking some great pictures.

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Summer 2015

Well it’s definately the end of the summer. Mid September and you can smell the aroma of fires at night time as it gets cooler.
No need for a fire to be lit here as yet but the end of the summer raises the issue of overheating again. This year there was very little overheating, due partly to a poor summer and partly due to setting the heat recovery system to run a bit differently. We found a setting for the summer bypass in the setup menu which prevents the bypass opening below a certain temperature. This was set to 18 deg C, which did restrict the times the bypass opened. By adjusting this down to its minimum of 13 deg c during the summer meant that the house could cool itself a bit more.
We are still a bit undecided whether to put in a brise soleil over the windows on the south side to give shading in the summer. We might be glad of it if we have a hot summer.

Advanced notice to everyone. NZEB open days / international Passive House day 13-15th November

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Temperature Profile 2014

See temperatures for 2014.




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Temperature Profile 2013

Since the end of January 2013, we have been keeping a record of the internal & external temperatures. The thermometer keeps a record of the daily minimum & maximum temperatures and has a wireless sensor that is mounted outside in the shade.

We also record the number of hours the immersion heater is on and the number of fires lit . This all gives a good indication of the energy performance of the house.

The only item not included is the amount of time the underfloor heating is on, there are 3 x 200W elements in the house (utility, bathroom & en-suite). This is reflected in the energy use which currently stands at 20.92kWh per day on average (since electricity connected). This will go down as we get into the summer.

Energy Monitor & Thermometer

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Heat Recovery System

There are a few fundamentals to a Passive House; high levels of insulation, building design & orientation, air tightness and a good heat recovery system.

The heat recovery system is required to bring in fresh air to the house & expel stale air. The two air streams pass through a heat exchanger to raise the temperature of the incoming air. We did a bit of research and were looking for two things from our unit, Passiv House certification & high efficiency. We wanted Passiv House certification so if in the future we go down the route of certifiying the house, we get maximum benefit from the unit in the calculations. A non certified unit will automatically have a derating of its stated efficiency whenthe calculations are made.

The house is actually entered onto the passive house database based on its preliminary & design calculations:

Secondly a high efficiency was required to reduce the amount of heat lost from the building.  The unit we chose was a PAUL Novus 300. This is a German made unit with a stated efficiency of 92%. This is highly impressive to think that 92% of the heat expelled from the house is recovered back into the incoming fresh air.

The unit appears to work OK and it is a nice compact unit that is wall mounted (albeit supported from the worktop as well). The benefits of a HRV unit as well as keeping the air fresh inside are that damp air from bathrooms & utility room is removed. Drying clothes in the utility room is great and towels dry nicely in the bathrooms.

Utility Room showing PAUL HRV unit

The unit is also fitted with a frost heater (black box above right of the HRV unit) which pre-heats the incoming air if it is too cold (This prevents any danger of the heat exchanger freezing and getting damaged).

The downside of this unit is the lack of any feedback. There is no display showing temperatures or whether the summer bypass or frost heater are operational. I presume that being a German unit the principle is that it works and you don’t need any confirmation of that fact. This was highlighted recently when the unit kept cutting out in freezing conditions and it was only after several conversations with the manufacturer that I realised that the control for the frost heater was setup incorrectly by the installers. A change of setting and now the frost heater delivers just enough heat to maintain a temperature above freezing into the unit.

The second downside of the unit was the installers, they didn’t seem to have much knowledge of the unit, the duct installation & insulation was poor and the unit had to be changed as it was installed or set up incorrectly. During the sumer I will re insulate some of the ducts as they are not properly vapour sealed and we get condensation dripping off on top of the unit and sometimes seeping down the back of the unit. Also no coordination was made with the electricians or builders despite them all being on site at the same time so no provision was made for cable routing.

I would recommend the unit especially as a new version looks to be coming out with an integral frost heater, but would recommend that the builders install the ductwork and the unit. The suppliers will have to  do the commissioning. Installing temperature probes into the ducts would be recommended also in case you want verification.

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Summer 2012

Well the summer is over and we can report on the operation of our house over the period.

Temperature wise, the house did get up to 26 deg when outside was warm and sun was shining. We do have alot of glazing with no shading system or overhangs. This is due to the fact it is a 2 story house and the design of the house did not include them. The design ties in with local architecture where the roofs do not overhang at all.

The heat recovery system goes into summer bypass mode when the extract air becomes too warm (currently set to over 23 deg) and in this mode it brings in fresh air without any heat recovery.

The other method of keeping the house cool is to open windows & doors, however with an inquisitive little baby in the house we had to keep doors closed alot of the time. For next year we will get door brakes fitted so we can open the door a little without any danger of them swinging open or a little one climbing out.

Further down the line we may put in some shading system, especially over the ground floor windows & doors.

Overall we loved the house during this period, it was always lovely and warm (even when the sum wasn’t shining) and was wonderfully bright.

As a bonus, during the summer the sun swings right round and shines on the North side of the house in the evening. It allows for a lovely sit on the porch or in the hanging chair on the landing.

We just need to get the garden sorted for next year now, a major task!!!

A blank canvas ready to develop. (Maybe just put grass seed down!)

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Energy Use – May

The leaves are growing on the trees and the sun is sitting higher in the sky so we should no longer overheat. It did reach 22 deg one sunny day recently but very comfortable.

We did also have the stove on last week for one evening because it was quite chilly, but a couple of hours later and the house was lovely and warm!!!

We invested in an energy monitor a couple of months ago. A transmitter fits around the cable into your electric meter and sends power usage information back to the display box inside. This displays current usage, cost, daily & monthly usage as well as having the facility to link to the PC for more detailed analysis. Where this really pays off is to instantly see if anything has been left on such as bathroom lights (which are currently higher wattage bulbs) or the underfloor cables in the bathrooms. It also means you can keep a tab on what your next bill might be like. Our first bills were for €208 & €275 for two months (a high amount but that included running underfloor all day) and the next bill is likely to be around €150 for two months.  This is pretty good considering this includes all our water heating, cooking (we cook alot!), washing (washing machine on every night) as well as lighting and any space heating via the underfloor cables in bathrooms.

We also have a tumble dryer but have not used it as the clothes dry perfectly in the utility room without it. This is the advantage of a heat recovery system. The damp air is constantly being drawn away from the room.


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March 29th – Solar Report

Sorry not been posting recently, but we have been a bit busy and we do not yet have a phone line in the house. Tomorrow that will change hopefully. Eircom expected to put line in (just as they go into examinership!!).

The weather here has been wonderful, up to 19 degrees with full sunshine for the past few days. This has led to the solar panels working well and getting a full tank of hot water (over 60 deg C for the full 400 litres). Immersion has been turned off now and the energy usage of the house has dropped. We have an energy monitor attached to the live feed into the meter. The base load of the house seems to be around 100W which includes for the heat recovery system as well as the fridge freezer and any appliances we have forgotten to turn off! The main users of energy are now the appliances for cooking & washing / dishwasher.

The sunshine has also heated the house up considerably, with no shading from the trees (no leaves yet) and the lower position of the sun, this has increased the solar gain. The temperature gets up to 24 deg inside. Opening the door or closing blinds / curtains helps and the feel of the house is of a hot summer day. As the leaves on the trees grow and the higher angle of the sun reflects more heat away from the glazing this potential overheating should abate. No complaints though, it is Ireland not the South of Spain!

Will fill in the gaps as we go along.

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Week 12

Well we are so close now!

The lads from Flaherty & Goaley are finished now, they completed the woodwork internally and have completed the canopy / entrance ramp outside the front door. They also installed worktop , sinks & cabinets in the utility room. The quality of workmanship has been excellent and we would not hesitate in recommending them. They are off to Sweden to carry out more work for Lars so good luck to them all.

Denise has carried on with the painting in amongst the other workers and she is getting close to completion, next week hopefully!

The kitchen didn’t go in this week as we hoped, another job overran and the van broke down on Friday so no kitchen yet. We collected the wooden worktops from the UK this week together with stored appliances and the remaining appliances were delivered on Thursday so we are ready to go!

The plumber didn’t turn up either, probably hoping to get a good run next week.

The ESB did arrive to connect the pole up to the grid and put in a connection to the meter box. We just await completion by the electrician before the final connection is made. Collected the light fittings this weekend in preparation!

Next week will be busy – kitchen , painting, electrician & plumber all on site Monday together with Peter & John for final bits and pieces.

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